Electric-motor control.



l?. N. JONES.

ELECTRIC` MOTOR CONTROL.

APPLIOATIQN FILED SEPT. 2s, 1912.

1,961,299. mmm@ 1 3, 1913.

3 SHBETS-SHEET 1.

JWM

lIL

P.' N. JONES.

ELEQLRIC MOTOR CONTROL.

.PPLlUATION FILED SEPT. 23, 1912. ,gljggg Patented May 13, 1913.

3 SHEETSr-SHEBT 2.

wimxssas g INVEN'ron P. N. JGNES.

ELEGTBIG MOTOR GNTROL.-

QLIUATION FILED SEPT. 2s( 1912.

3 SHEETS-SHEET 3.

.Patented lll'ay l, i913.

l?. HE? w u UNITED sTATns rnTnT rivier..

:PEARL n. Jones, or rirrsnunori, rnivnsrnvania.

ELECTR-IC-MTR CONTROL.

Specification of'lietters Patent:-

Application filed September 23, i912. Serial No. 721388.

1 Figure is a general diagram illustrating my invention; F ig. 2 is atable or diagrain indicating the positions of the several switches inthe dierent control steps or notches; Fig. 3 is a diagram showing themotor circuits in the different control steps lor notches; Fig. 4 vis adetail wiring diagram Fig. 5 is a View similar to Fig. 2, but

showing a modification; and Fig. 6 is a diagram showing themodifiedcircuit connections-effected by the modification of Fig. 5.

My invention has relation to certain new and useful 'improvements in thecontrol of electric motors, and more particularly, to improvements inseries-parallel control Isystems therefor. i

4The object of my invention is to provide a `method of, and means-for,controlling a plurality of electric motors, especiallyapplicable'to series-wound car motors, and which will greatly simplifythe car wiring and cir.- cuit connections; which will ohviate eitherentirely or to a very large extent the breaking of the initial seriesVconnections of the motors; and which effectively guards against shortcircuits or destructive arcing at the switch contacts,

A further object of my invention is to largely eliminate the use ofexternal resistance, and thereby decrease the current loss in 4startingthe motors. x

ln accordance with the preferred form of my invention, a plurality ofmotors are connected in series for the first running position and'arechanged to parallel relation without breaking the initial seriesconnections, by lproviding parallelv circuit connections so arranged asto reverse the flow of current through both the fields and the armaturesof some of the motors. For the intermediate steps, the motors areconnected in series-parallel groups, and one or more of the motors areshort-circuited without break-l in their series connections.

j y invention also comprises various other featureswhioh will. behereinafter fully described. i A, l

Patented May 13, 1913. i

Referring rst to the general 'diagram` shown in F 1g. l, l haveillustrated four series-wound motors marked, respectively, 1,

2, 3 and 4, connected in'series between vthe trolley and ground. ,'fhearmatures of the motorsare designated A', A, A3 and A, respectively, andtheir field windings are respectively designated as F', F2, F3..an d F4,

A, B, C, D,Y E, l?, :R and T designate switches or switch contacts whicheffect the various circuit changes employed in the system of control.The arrangement and mode of connection of these switches will be bestunderstood by an examination of Fig. l.-

The table shownin Fig. 2 indicates the positions of these switches atthe dilerent controller notches, the latter being indicated in thecolumn at the left-hand side of the table, and the columns of the tablebeing headed by letters corresponding to the letters given the differentswitches in' Fig. i.

The presence of a black dot in any square'o'f.

the -table indicates that the switch desig-` nated at the head of thecolumn in which it n occurs is closed, whilethe absenceof such a dotindicates that the switch the column is open.

At the first controller notches, the 'switch A and switch T are closed,the other switches, The closing of' these two j,

being open.

at the 'head vof switches causes the current to flow through" theresistance R and through the four ino'- tors in series to ground, asindicated inthe first position shown in Fig. 3. 'This is a startingposition or notch only." The first running position is that shown asIthe second position of F ig. 8, in which the resist-ancey has beenshort-circuitedby the closingof `the switch R.

At the third notch, switch A is "opened, the switch C is closed,switches'R andT'ref maining closed, the switch A having' been,

opened an instant after the switchC 'is closed. In this position motorsl and 2 are seri s.

jioo

sho t-circuited, and motors 3 and 4.are in,` At the fourth notch,lswitchE is" closed, the other switches remaining-iii posi! Q tion. Theclosingof switch E 4establishesa ground connection for motors 41Ia`nd,l2,andf these motors are now in series-parallelwith' the motors 3and 4, but with the 'currei'itf`y flowing through them inthereversedirection.

At the neXt or fifth. position, switch B is closed, switches C, E, R andT remaining closed, as before, the closing of the switch B acting toform asliort circuit for motor No.l 2. Motor No. l is now in parailelrelation to motors 3 and 4, which are in series, but with the currentstill flowing in the reverse direction through motor No. l. In the sixthposition, switch D is closed and switches B', E, R and T remain closed,switch C having beenopened an instant after closing switch D; andthemotors 2 and 3 are no-w short-circuited, and motors l and 4 areconnected in parallel. In the seventh position, switches B, D, E, F, Rand T are closed, the closing of the switch F establishing anladditional ground connection -between ino-tors 2 and 4, and the fourmotors are connected in parallel. Positions 2, 4, 7 are runningpositions: the other positions are transition positions.

It will be seen that in effecting the change` from full series to fullparallel relation of the four motors, the initial series connectionsbetween they motors has not been broken, but that these connections havebeen maintained and that the various changes have been effected byshort-circuiting one or more motors and by establishing circuit connections of a character to cause the current to flow through both thefields and armatui'es of some of the motors in a direction reverse tothat in which it flowed in the series position. My invention thereforemakes it unnecessary to bring the terminals of each motor element to thecontrolling switches, thereby greatly simplifying the controllingapparatus, as well as the-car wiring. In some cases, however, as in thecase of an especially heavy. car equipment, it may be advisable tointerpose an additional step between the steps 6 and 7 of F ig. 8, andin which, instead of passing directly from the condition of position 5to t-he full parallel relation of position `7, the motors aresuccessively connected in parallel. This modification is illustrated onSheet 3 in Figs. 5 and 6. In this form, the first four steps aresubstantially the same as the first four steps in the arrangementillustrated in Figs.

l, 3.and 4. At the fifth step, however, the switches C', D, E, R and Tare closed, the other switches being open. circuit conditionsrepresented in the fifth position of Fig. 6, motors l and 2 having thecurrent reversed therethrough and being connected in series,motcr No. 4being in parallel with motors ji and 2, and motor No. 3 beingshort-circuited. 0n the sixth step, the switches D, E, F, R and T areclosed, which places motors 3 and 4 in parallel with each other, withmotors 1 and 2 short-circuited. In the seventh step', switches B, D,

F, R and T-are closed, giving the circuit conditions shown in theseventh position of This gives the employed for carrying out my improvedmethod of control. I have, however, designed apparatus for this purpose,which is illustrated diagrammatically in Fig. 4, and which will now bedescribed. In this figure, the corresponding parts are given the samereference characters as in the other figures,

but are shown more in detail. In this figure, MC designates a mastercontroller, comprising the usual rotary drum having thereon a pluralityof contacts c, adapted to connect the contact fingers f in various waysin the different positions of the drum. The several switches beforereferred to are here shown as consisting each of asolenoid, the plungersof the solenoid being connected nto the movable contact members of theswitches; and `the contacts of the master controller being arranged tocontrol the currents of the solenoids.

By referring to Fig. l, it will be seen that it is necessary tosoarrange the switches A and E and also the switches C and F as to provideagainst any possibility of the two switches of either pair being closedat the saine time, as such closure would effect a direct connection fromtrolley to ground. For this purpose, switches A and E and switches C andF are electrically interlocked. This is effected as follows:

.The solenoid winding of switch A is carried. through a pair ofseparated contacts 5, which are arranged to be bridged by a contact 6,carried by the lever E of the switch E, and which lever also carries themovable contact 7 of that switch. This circuit is further carriedthrough the two separated contacts 8, which are arranged to be bridgedby movable contact 9, having a plunger which extends within a solenoidwinding 10, which is connected in series between ""e contact 7 andground. In a similar manner, the winding of the solenoid' E is carriedthrough the two lcont-acts ll, arranged to be bridged by the contactlever A, of switch A, and also through contacts 12, arranged to bebridged by a movable contact 13, whose actuating plunger extends withina solenoid winding 14, which is in series between the movable contact ofswitch A and the aimature of motor No. 1.

Itwill be readily seen that by reason of the foregoing provisions,neither switches E or A can be closed without rst opening the circuit ofthe winding of the other noemen switch; and further, that the circuit ofeither switch can not be closed, so long as` any arc is being maintainedbet-Ween the main contacts of vthe other switch, as thesolenoid-operated contacts 9y and 13 will hold the circuit open, solong` as an arc is maintainedat such contacts, and current is flowingthrough the solenoid Winding 10.

The switches C and F are similarly interlocled, as Will be readily seenfrom llig. el, without a detailed description thereof.

MR designates-a master reverser switch having ahead .andreversepositions, respectively. The, contacts of this svvitch in itsl aheadposition close the .circuit of a solenoid S, While the, contacts in itsreverse position close the circuit of the solenoid S. The solenoids S,S', are connected to the shaft lo, which operates a series of reversinglswitches RS, RSZ-RS?, RS4, for the respective motors.

It will be unnecesary to trace the circuits in Fig. 4in-the variouspositions of the several switches, as this can `best 'be done byreference to F ig. 6. To facilitate this, the control Wires have beenindicatedv by lighter lines,.wliile the motor circuit Wires areindicated by heavier' lines. By tracing these circuits, itvvill be foundthat the respective positions of the master cont-roller effect theircuit relations shown in. Fig. 3.

It will be obvious that instead of employ-A ing solenoid-actuatedswitches, I may employ any other Well known or suitable form,

'and thatvarious other' changes may be made in the details of the switchcontacts vand their Wiring connections Within the scope of the appendedclaims.

In describing Fig. l, it has been assumed that a certain side of 4thecircuit shown is trolley and the other .side ground, but it is obviousthat it is immaterial Which sideis considered the supply and which sidethe, return side of the circuit. 1

The advantages of my invention will be apparent to those skilled in theart, since it provides a method of and means for the control of aplurality of electric motors in which the acceleration of the motors iseifected by successive steps, which gradually increase the speed andgive easy running and freedomffrom vjerks. The method of changingthemotors fromseries to parallel relation Without disconnecting theirterminalsgreatly simplifies the apparatus and circuit connections andreduces the amount of arcing at the switch contacts. These changes areeitected Without the use of eX- ternal resistance,'such resistance beingused only momentarily in starting, and in some cases, even thismomentary use may be dispensed with. I claim: l. Inthe controlof .threeor morev electric motors, the .steps vvhioh consist' -estabp lishing asmany parallel ypaths through the motors as there are motors, a'ndmaintaining a series connection 'between the motorsr` motors,v themethod which consists intih"ang'-'l ing the motors from series to'pa.rallelrelation v byv successively establishing parallel i'ciufrrent"paths through the motors and maintaining at least two ol thel motorsactively in oir cuit throughout said changes, andy also' m'ain', taininga series connection between the motors until there are as many of such'paths as there aremotors; substantially as cle-"V scribed. j t 3. rlhemethod of controlling electric mof' tors, which consistsin connectinga"plural`--` 8'5 ity of them in series, then 1n series-parallel groups,and finally .inparallel byestabli'shr* ing parallel circuits whichreverse the cur- H rent flow 1n some of the motors, 'and vmantaining aseries ,connection betvv'een' themei tors While effecting the circuitchanges*,sb-I stantially as described;v 4. The vmethod 'of controllingele tr motors, which consists in connecting a rality of them in series,then'short-c re ing one or moreof the motors, theiifebfl necting them inseries-parallel groupsflafd" then successively connecting them in'p rl#allel by establishing parallel lcircuits "w n reverse the currenttlovvin some of thel'. and maintaininga series connection betvvee themotors While eiecting vthe 'circuit changes; substantially as described.

5. The herein'descrihed method ot coin trolling electric motors Whilepermanently' connected .in series, which consists in shortcircuiting twooi the motors, then connecting them in series-para-lle'l groups, thenshort-'circuiting one motor of one group and connecting the remainingmotor of that group in parallel With the tivo motors of the other group,then short-circuiting a motor of the other group and placing theremaining tvvo motors in parallel, and i'inally connecting all fourmotors in parallel, and eiecting said steps While maintaining a seriesconnection of the motors by establishing parallel circuitconnections'which reverse the flow of current through some of them,

loe

ies.

substantially as described.

6. The method lof controlling a plurality of series-connected electricmotors, `which consists in short-circuiting some of the;

motors While leaving the others in series,

then connecting the short-circuited motors to ground and thereby formingparallel current paths through the tivo sets of motors, and maintaininga series connection bet-Ween all the motors while effecting saidchanges, and `also maintaining at least two of the substantially asdescribed.

motors actively in circuit; substantially as n described.

. '.ilhe method of controlling a plurality of series-connected electricmotors, which cons sts in short-circuiting some of. lthe motors whileleaving the other motors in series, connecting the short-circuitedmotors to ground and 'thus forming parallel current paths through thetwo sets of motors,

' series, of control apparatus therefor, having contact and circuitconnections'arranged to establish as many parallel paths through themotorsas there are motors, while maintaining a series connect-ion of themotors;

9.-'1`he combination with a plurality of electric motors permanentlyconnected in a. series, of controlling apparatus therefor having aplurality of contacts, and circuit' connections which are arranged toconnect the motors in series parallel groups and then in parallel whilemaintaining their series .connectionsg substantially as described. 1

l0. The combination with a plurality of electric motors connected in aseries, of controlling apparatus having' switching l means arranged toshort circuit some of the motors while maintaining their seriesconnection, and other switching means arranged to establish parallelconnections therefor between the two terminals of the circuit and of acharacter to cause a reverse -flow of current through some ofthe motors,

some of said switching means being electrically related or interlockedyso as to prevent closing of one switch while another is closed,substantially as described.v

11. The combination withf'a plurality of electric motors connected in aseries, of con trollingapparatus having switching means arranged toshort circuit some of the motors rent through some of t-he motors, someof' 4saiol switching means being related or interlocked so as to preventclosing of one switch while another is scribed. i y

. l2. Thev combination with a plurality of electric motors connected ina series, of controlling apparatus having switching means arranged toshort circuit some ofthe .motors while maintaining their seriesconnection, and other switching means arranged to establish parallelconnections therefor between the two terminals of the circuit 'and of acharacter to cause a reverse flow of current through some of the motors,some of said switching means being electrically related or'interlockedso as to prevent closing of one switch while current is flowing throughanother; substantially as described..

In testimony whereof, I have hereunto set my hand. PEARL N, JONES.

closed; substantially as de- Witnesses:

JEssE B. HELLER, GEO. H. PARMELEE.

